Effect of Mycotoxins in Silage on Biogas Production.

Mycotoxins can pose a threat to biogas production as they can contaminate the feedstock used in biogas production, such as agricultural crops and other organic materials. This research study evaluated the contents of deoxynivalenol (DON), zearalenone (ZEA), fumonisin (FUM), and aflatoxin (AFL) mycotoxins in maize silage prior to it being processed in a biogas plant and in digestate produced at the end of the anaerobic digestion (AD) process. In the experiment, three samples of silage were collected from one silage warehouse: Variant 1 = low contamination, Variant 2 = medium contamination, and Variant 3 = heavy contamination, which were subjected to investigation. A significantly reduced biogas production was recorded that was proportional to the increasing contamination with molds, which was primarily due to the AD of silage caused by technologically erroneous silage treatment. The AD was connected with changes in silage composition expressed by the values of VS content, sugar content, lactic acid content, acetic acid content, and the ratio of lactic acid content to acetic acid content. The production of biogas and methane decreased with the increasing contents of NDF, ADF, CF, and lignin. The only exception was Variant 2, in which the content of ADF, CF, and lignin was lower (by 8-11%) than that in Variant 1, and only the content of NDF was higher (by 9%) than that in Variant 1. A secondary factor that also correlated with changes in the composition of the substrate was the development of undesirable organisms, which further contributed to its degradation and to the production of mycotoxins. It was also demonstrated in this study that during the AD process, the tested mycotoxins were degraded, and their content was reduced by 27-100%. Only the variant with low mold contamination showed a DON concentration increase of 27.8%.

Possibility of using tannins to control greenhouse gas production during digestate storage.

The presented paper deals with the testing of a possibility to reduce emissions of undesirable greenhouse gases (CH4, CO2; NOx) and their mixture (biogas) during the storage of digestate using applications of secondary plant metabolites (tannins). The experiment was conducted in laboratory conditions in which the digestate was placed in fermentation chambers. Prior to the fermentation process, preparations were applied to the digestate, which contained tannins: Tanenol Antibotrytis (TA), Tanenol Clar (TC) and Tanenol Rouge (TR) in three concentrations (0.5, 1.0 and 2.0% w/w). The application of these preparations demonstrably affected the production of biogas and the contents of CH4, CO2 and N therein. The application of TR preparation in the concentration of 1.0% and 2.0% significantly reduced the production of biogas as compared with all variants. The preparation further inhibited the process of CH4 development. In contrast, the other preparations with the content of different kinds of TA and TC increased the production of biogas (on average by 15%), CH4 (on average by 7%) and CO2 (on average by 12%) as compared with the control variant and TR variant. These two variants reduced the concentration of N in biogas on average by 38%. Thus, the tested Tanenol tannin preparations can be used in different concentrations either to control emissions of greenhouse gases during the storage of digestate or, in case of increased production of CO2 for its reuse in order to increase methane yields in the process of anaerobic fermentation.

Microbiological insight into various underground gas storages in Vienna Basin focusing on methanogenic Archaea.

In recent years, there has been a growing interest in extending the potential of underground gas storage (UGS) facilities to hydrogen and carbon dioxide storage. However, this transition to hydrogen storage raises concerns regarding potential microbial reactions, which could convert hydrogen into methane. It is crucial to gain a comprehensive understanding of the microbial communities within any UGS facilities designated for hydrogen storage. In this study, underground water samples and water samples from surface technologies from 7 different UGS objects located in the Vienna Basin were studied using both molecular biology methods and cultivation methods. Results from 16S rRNA sequencing revealed that the proportion of archaea in the groundwater samples ranged from 20 to 58%, with methanogens being the predominant. Some water samples collected from surface technologies contained up to 87% of methanogens. Various species of methanogens were isolated from individual wells, including Methanobacterium sp., Methanocalculus sp., Methanolobus sp. or Methanosarcina sp. We also examined water samples for the presence of sulfate-reducing bacteria known to be involved in microbially induced corrosion and identified species of the genus Desulfovibrio in the samples. In the second part of our study, we contextualized our data by comparing it to available sequencing data from terrestrial subsurface environments worldwide. This allowed us to discern patterns and correlations between different types of underground samples based on environmental conditions. Our findings reveal presence of methanogens in all analyzed groups of underground samples, which suggests the possibility of unintended microbial hydrogen-to-methane conversion and the associated financial losses. Nevertheless, the prevalence of methanogens in our results also highlights the potential of the UGS environment, which can be effectively leveraged as a bioreactor for the conversion of hydrogen into methane, particularly in the context of Power-to-Methane technology.

Assessment of digestates prepared from maize, legumes, and their mixed culture as soil amendments: Effects on plant biomass and soil properties.

Digestate prepared from anaerobic digestion can be used as a fertilizer, as it contains ample amounts of plant nutrients, mainly nitrogen, phosphorous, and potassium. In this regard, digestates produced from mixed intercropped cereal and legume biomass have the potential to enrich soil and plants with nutrients more efficiently than monoculture-based digestates. The objective of this study was to determine the impact of different types of digestates applied at a rate of 40 t·ha-1 of fresh matter on soil properties and crop yield in a pot experiment with lettuce (Lactuca sativa) as a test crop. Anaerobic digestion of silages was prepared from the following monocultures and mixed cultures: broad bean, maize, maize and broad bean, maize and white sweet clover, and white sweet clover. Anaerobic digestion was performed in an automatic custom-made system and applied to the soil. Results revealed that fresh and dry aboveground biomass as well as the amount of nitrogen in plants significantly increased in all digestate-amended variants in comparison to control. The highest content of soil total nitrogen (+11% compared to the control) and urease (+3% compared to control) were observed for maize digestate amendment. Broad bean digestate mediated the highest oxidizable carbon (+48%), basal respiration (+46%), and N-acetyl-ß-D-glucosamine-, L-alanine-, and L-lysine-induced respiration (+22%, +35%, +22%) compared to control. Moreover, maize and broad bean digestate resulted in the highest values of N-acetyl-ß-D-glucosaminidase and ß -glucosidase (+35% and +39%), and maize and white sweet clover digestate revealed the highest value of arylsulfatase (+32%). The observed differences in results suggest different effects of applied digestates. We thus concluded that legume-containing digestates possibly stimulate microbial activity (as found in increased respiration rates), and might lead to increased nitrogen losses if the more quickly mineralized nitrogen is not taken up by the plants.

Archaeal community dynamics in biogas fermentation at various temperatures assessed by mcrA amplicon sequencing using different primer pairs.

In this study, the taxonomic and functional diversity of methanogenic archaea in two parallel 120 l fermenters operated at different temperatures and fed with maize silage was estimated by mcrA metabarcoding analysis using two typical primer pairs (ML and MLA) amplifying part of the functional methyl coenzyme M reductase (mcrA) gene. The alpha diversity indices showed that the ML primer pair detected a higher Operational Taxonomic Unit (OTU) abundance compared to the MLA primer pair and methanogen diversity was significantly lower in the 60 °C fermenters. The beta diversity analysis showed the methanogenic community clustered together at 50 °C and 40° and was statistically different from the 60 °C community. Similar, to alpha diversity, beta diversity was also significantly different between primer pairs. At all temperatures analysed, the primer pairs showed a different abundance of the different methanogenic OTUs, e.g. more OTUs relative to Methanoculleus sp. with the ML primer pair, and more OTUs corresponding to Methanobacterium sp. with the MLA primer pair. Moreover, OTUs corresponding to Methanosphaera sp. and Methanobrevibacter sp. were found only by using ML primer pair, while the MLA primer pair detected sequences corresponding to Methanothrix sp.

Plant Byproducts as Part of Edible Coatings: A Case Study with Parsley, Grape and Blueberry Pomace.

Studies dealing with the development of edible/biodegradable packaging have been gaining popularity since these commodities are marked as being ecofriendly, especially when byproducts are incorporated. Consequently, this study aimed at the development of chitosan-based coatings with plant byproducts. Their sensory properties, colour attributes, occurrence of cracks in microstructure and biodegradability were analysed. Coatings containing grape and blueberry pomace had statistically significantly (p < 0.05) higher levels of colour intensity. Coating samples were characterised by lower aroma intensity (3.46-4.77), relatively smooth surface (2.40-5.86), and low stickiness (2.11-3.14). In the overall hedonic evaluation, the samples containing parsley pomace in all concentrations and a sample containing 5% grape pomace achieved a statistically significantly (p < 0.05) better evaluation (5.76-5.93). The lowest values of the parameter ΔE2000 were recorded for the sample containing 5% parsley pomace (3.5); the highest was for the sample with 20% blueberry pomace (39.3). An analysis of the coating surface microstructure showed the presence of surface cracks at an 80 K magnification but the protective function of the edible coating was not disrupted by the added plant pomace. The produced samples can be considered to have a high biodegradability rate. The results of our experimentally produced coatings indicate their possible application on a commercial scale.

Aluminum contamination of food during culinary preparation: Case study with aluminum foil and consumers' preferences.

The aim of the work was to estimate the degree of aluminum leakage from aluminum foil during baking process of selected food/meals. The experiment included 11 different types of food (Atlantic salmon Salmo salar, mackerel Scomber scombrus, duck breasts, cheese Hermelín, tomato, paprika, Carlsbad dumplings, pork roast, pork neck, chicken breasts, and chicken thighs) baked both marinated and not marinated. The aluminum content was measured by AAS and ICP/MS methods. The highest aluminum increase was observed in the samples of marinated Salmo salar (41.86 ± 0.56 mg/kg), Scomber scombrus (49.34 ± 0.44 mg/kg), and duck breast (117.26 ± 1.37 g/kg). The research was also supported by the survey that consisted of 784 respondents with different sociodemographic characteristics. The study clearly showed the occurrence of aluminum contamination of food when it is prepared by baking in aluminum foil. It cannot be concluded that aluminum leakage will occur with each type of food. The aluminum contents found among investigated samples are not alarming, though the increase was measured up to 40 times. On the other hand, revealed aluminum contents can represent a risk for younger/smaller children and for individuals with diagnosed certain ailments.

Occurrence of Thermophilic Microorganisms in Different Full Scale Biogas Plants.

BACKGROUND: In recent years, various substrates have been tested to increase the sustainable production of biomethane. The effect of these substrates on methanogenesis has been investigated mainly in small volume fermenters and were, for the most part, focused on studying the diversity of mesophilic microorganisms. However, studies of thermophilic communities in large scale operating mesophilic biogas plants do not yet exist. METHODS: Microbiological, biochemical, biophysical methods, and statistical analysis were used to track thermophilic communities in mesophilic anaerobic digesters. RESULTS: The diversity of the main thermophile genera in eight biogas plants located in the Czech Republic using different input substrates was investigated. In total, 19 thermophilic genera were detected after 16S rRNA gene sequencing. The highest percentage (40.8%) of thermophiles was found in the Modrice biogas plant where the input substrate was primary sludge and biological sludge (50/50, w/w %). The smallest percentage (1.87%) of thermophiles was found in the Cejc biogas plant with the input substrate being maize silage and liquid pig manure (80/20, w/w %). CONCLUSIONS: The composition of the anaerobic consortia in anaerobic digesters is an important factor for the biogas plant operator. The present study can help characterizing the impact of input feeds on the composition of microbial communities in these plants.

The diversity of sulfate-reducing bacteria in the seven bioreactors.

Anaerobic technology has a wide scope of application in different areas such as manufacturing, food industry, and agriculture. Nowadays, it is mainly used to produce electrical and thermal energy from crop processing, solid waste treatment or wastewater treatment. More intensively, trend nowadays is usage of this technology biodegradable and biomass waste processing and biomethane or hydrogen production. In this paper, the diversities of sulfate-reducing bacteria (SRB) under different imputed raw material to the bioreactors were characterized. These diversities at the beginning of sampling and after cultivation were compared. Desulfovibrio, Desulfobulbus, and Desulfomicrobium genus as dominant among sulfate reducers in the bioreactors were detected. The Desulfobulbus species were dominant among other SRB genera before cultivation, but these bacteria were detected only in three out of the seven bioreactors after cultivation dominant.

A New Combination of Substrates: Biogas Production and Diversity of the Methanogenic Microorganisms.

Agriculture, food industry, and manufacturing are just some of the areas where anaerobic technology can be used. Currently, anaerobic technologies are mainly used for wastewater treatment, solid waste treatment, or for the production of electrical and thermal energy from energy crops processing. However, a clear trend is towards more intensive use of this technology in biomass and biodegradable waste processing and hydrogen or biomethane production. An enormous number of anaerobic digesters are operating worldwide but there is very little information about the effect of different substrate combinations on the methanogens community. This is due to the fact that each of the anaerobic digesters has its own unique microbial community. For the most effective management of anaerobic processes it would be important to know the composition of a consortium of anaerobic microorganisms present in anaerobic digesters processing different input combinations of raw material. This paper characterizes the effect of the input raw materials on the diversity of the methanogen community. Two predominant microorganisms in anaerobic digesters were found to be 99% identity by the sequences of the 16S rRNA gene to the Methanoculleus and Thermogymnomonas genera deposited in GenBank.

Novel insight into the process of nutrients removal using an algal biofilm: The evaluation of mechanism and efficiency.

Eutrophication of water by nutrient pollution remains an important environmental issue. The aim of this study was to evaluate the nutrient uptake capacity of an algal biofilm as a means to treat polluted water. In addition, the study investigated the nutrient removal process. The algal biofilm was able to remove 99% of phosphorus within 24 hours of P addition, with the PO4-P concentration in inflowing water ranging from 3 to 10 mg L-1. Different patterns of phosphorus and nitrogen removal were observed. Daily quantity of removed NO3-N ranged from 2 to 25% and was highly dependent on solar irradiance. Precipitation of phosphorus during the removal process was studied using X-ray diffraction analyses and was not confirmed in the biofilm. The biofilm system we constructed has a high efficiency for phosphorus removal and, therefore, has great potential for integration into wastewater treatment processes.